The determination of the positioning of a point in space and the determination of the attitude of any object are problems that affect many technical fields.
The various solutions generally provided have to eliminate any position or attitude ambiguity, respond to a more or less stringent dynamic of the systems and provide a high accuracy, in particular in the aeronautical field.
In the systems for detecting position and attitude of objects in space that provide an accuracy of a few millimeters in position and a degree in attitude, there are many applications in various fields.
These systems are used in aeronautics, to detect head posture, notably for the headsets of fighter airplanes, military, civilian or para-civilian helicopters. In the latter para-civilian application case, it may relate to offshore rescue missions for example. They are also used for the detection of simulation headsets, this detection can then be combined with an oculometry device, also called eyetracker, to detect the position of the look. In the field of virtual reality and games, there are also many applications for these systems.
More generally, in the field of generic posture detection, there are also many applications, notably in the medical field for teleoperations and instrument monitoring, in the field of position monitoring for servo-controlled machine tools or remote control, and finally for cinema, in order to reproduce movements in synthesis images.
These various applications have technical solutions that meet more or less stringent requirements.
Regarding applications with low constraints, notably in terms of accuracy, there are various systems for detecting position and/or orientation of objects.
For example, devices with camera-based patch or form recognition use drawings printed on an object. A number of cameras observe the scene and determine the spatial configuration of the observed drawing.
There are also devices with camera-based sphere recognition, which are used, for example in the cinema, to reconstruct human movement. The device uses a number of cameras which observe reflecting spheres and determine their trajectory.
Finally, there are ultrasound positioning devices that rely on the principle of triangulation between ultrasound emitters and receivers.
Concerning more powerful applications, in particular in the aeronautical field, the devices for detecting posture of headsets in aircraft use two main techniques which are electromagnetic posture detection and electro-optical posture detection.
Electromagnetic posture detection requires devices comprising means of emitting an electromagnetic field and receiving sensors on the headset making it possible to determine their position relative to the emitter.
Electro-optical posture detection generally requires motifs of light-emitting diodes, also called LEDs, positioned on the headset and a number of camera-type sensors mounted in the cockpit making it possible to determine the spatial configuration of an LED motif.
To improve performance, it is commonplace to combine other devices comprising sensors of gyroscopic, accelerometric or magneto-metric types. This hybridization of sensors makes it possible to improve the dynamic performance characteristics or eliminate an orientation ambiguity. These sensors do not modify the static positioning performance characteristics of the detection devices cited previously.
However, these solutions have a certain number of drawbacks and limitations, particularly in the aeronautical field.
Regarding the electro-optical devices, the map of the cockpit or more generally the topology of the area containing the object must be known. In aeronautics, this topology can be subject to deformations or be difficult to map.
Moreover, these same devices require a number of cameras and a number of sensors. The position calculations demand numerous resources and the real-time analysis is complex to implement.
Furthermore, the diffusion in the detection area of the light from the LEDs does not make it possible to completely overcome the disturbances from the light environment of the cockpit due to the sun or to spurious reflections on the canopy.
Regarding the electromagnetic posture detection devices, robust solutions are difficult to implement.
In particular, in the aeronautical field, spurious radiations and electromagnetic disturbances can degrade the performance characteristics of the existing systems.